(19)
(11) EP 0 216 273 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
16.12.1987 Bulletin 1987/51

(43) Date of publication A2:
01.04.1987 Bulletin 1987/14

(21) Application number: 86112651

(22) Date of filing: 12.09.1986
(84) Designated Contracting States:
DE FR GB IT NL

(30) Priority: 18.09.1985 JP 20436185

(71) Applicant: NIPPON KOKAN KABUSHIKI KAISHA
 ()

(72) Inventors:
  • Ikariya, Takao c/o Patent Div. Nippon Kokan K.K.
     ()
  • Mizuguchi, Masatsugu c/o Pat Div. Nippon Kokan
     ()
  • Tajima, Osamu c/o Pat. Div. Nippon Kokan
     ()
  • Itagaki, Masanori c/o Pat. Div. Nippon Kokan
     ()
  • Sakai, Itaru c/o Pat. Div. Nippon Kokan
     ()

   


(54) Method of manufacturing diphenylmethane dicarbamic acid esters


(57) According to a method of manufacturing a diphenylmethane dicarbamic acid ester by reacting an N-phenyl carbamic acid ester with a methylating agent in an aqueous acid solution, the aqueous acid solution is an aqueous inorganic acid solution, and the concentration of the N-phenyl carbamic acid ester in the aqueous acid solution is not more than the solubility thereof at the reaction temperature.






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